External Donor Research Articles

Energy-transfer-enabled photocatalytic transformations of aryl thianthrenium salts

Aryl thianthrenium salts are valuable in photocatalysis but traditionally require external electron donors for activation. This study introduces an energy transfer (EnT) strategy for the activation of aryl thianthrenium salts using 2,3,4,5,6-penta(carbazol-9-yl)benzonitrile (5CzBN) as a metal-free photocatalyst, eliminating the need for external donors. Utilizing this EnT approach, we achieve C–H deuteration of arenes under visible light with CDCl3 as a deuterium source to synthesize various deuterated aromatic compounds, including important natural products and pharmaceuticals. Additionally, this strategy enables diverse functionalizations including borylation, arylation, cyanation, and selenylation, enhancing the applicability of aryl sulfonium salts in environmentally friendly photocatalysis.

Cost of COVID-19 vaccine delivery in nine States in Nigeria via the U.S. Government Initiative for Global Vaccine Access

BackgroundIn 2022, the U.S. Centers for Disease Control and Prevention collaborated with implementing partners, African Field Epidemiology Network and Sydani Group, to support COVID-19 vaccination efforts in Nigeria. To characterize the costs of COVID-19 vaccination, this study evaluated financial costs per dose for activities implemented to support the intensification campaign for COVID-19 vaccination.MethodsThis retrospective evaluation collected secondary data from existing expenditure and programmatic records on resource utilization to roll out COVID-19 vaccination during 2022. The study included incremental financial costs of the activities implemented to support an intensification campaign for COVID-19 vaccination across nine states and six administrative levels in Nigeria from the perspective of the external donor (U.S. Government). Costs for vaccines and injection supplies, transport of vaccines, and any economic costs, including government in-kind contributions, were not included. All costs were converted from Nigerian Naira to 2022 U.S. Dollars (US$).ResultsThe estimated financial delivery cost of the COVID-19 vaccination intensification campaign was US$0.84 per dose (total expenditure of US$6.29 million to administer 7,461,971 doses). Most of the financial resources were used for fieldwork activities (86%), followed by monitoring and supervision activities (8%), coordination activities (5%), and training-related activities (1%). Labor (58%) and travel (37%) were the resource inputs that accounted for the majority of the cost, while shares of other resource inputs were marginal (1% for each). Most labor costs (79%) were spent on payments for mass vaccination campaign teams, including pay-for-performance incentives. By administrative level, the largest share of costs (46%) was for pay-for-performance incentives at the community, health facility, or campus levels combined, followed by local government area level (24%), community level only (15%), state level (9%), national level (3%), campus level only (1%), and health facility level only (< 1%).ConclusionsFindings from the evaluation can help to inform resources needed for vaccination activities to respond to future outbreaks and pandemics in resource-limited settings, particularly to reach new target populations not regularly included in routine childhood immunization delivery.

The Effects of Internal Electron Donors on MgCl2-Supported Ziegler–Natta Catalysts for Isotactic PP

The electron donors (ED) in Ziegler–Natta (Z-N) catalysis are classified as internal electron donors (IED) and external electron donors (EED), and both IED and EED are indispensable components for enhancing the catalytic reactivity and regulating the stereoregularity of polyolefinic materials in a typical industrial Z-N catalytic process. With the intensive research on ED, the Z-N catalyst performances have experienced successive progress in the last few decades. Polypropylenes (PP) as a commodity polyolefin material, especially the isotactic PP (iPP), are produced in multi-billion pounds per annum by utilization of the various IED- and EED-assisted Z-N catalysts systems. In the course of developing Z-N catalysts, the ED constitutes a key component of the content and represents a significant area of future research. In this review, we introduced a concise overview of the functions of IEDs in the generations of Z-N catalyst systems and the widely used IED types (A total of 11 different types of IEDs are encompassed within this study) that have been developed so far. In addition, we focused on the coordination modes of different IEDs in the MgCl2-supported Z-N catalyst system and analyzed the effects of different types of IEDs on the PP isotacticity, regioselectivity, hydrogen sensitivity, and briefly introduced the application of environmentally friendly rosinate and salicylate IEDs.

Photochemical coupling reaction of phenacyl benzoate with acetone to form 1,4‐dicarbonyl compound enabled by charge transfer

AbstractPhotolysis of phenacyl benzoates tethered with a phenol or anisole in acetone resulted in the formation of 1,4‐dicarbonyl compounds, coupling products of the phenacyl moiety with acetone. The reaction occurs via electron and/or proton transfer from a triplet exciplex, leading to the formation of a phenacyl radical, which then adds to the enol form of acetone. The reaction also occurs in intermolecular fashion with external electron donors.

Bioaugmentation of microalgae fermentation with yeast for enhancing microbial chain elongation: In-situ ethanol production and metabolic potential

Anaerobic microalgae fermentation, leveraging its cost-effectiveness and the adaptability of mixed cultures, holds promise for carboxylate biosynthesis. Microalgae, with their abundant carbohydrates and proteins, stand out as an optimal substrate for this process among various options. Furthermore, microalgae fermentation not only shows the potential to mitigate risks associated with algae blooms but also aligns with the need for sustainable practices. However, the limited utilization rate of microalgae in anaerobic fermentation poses challenges to achieving high production rates of desired products. In this study, we implemented a bioaugmentation process with yeast to enhance carboxylate production performance of microalgae fermentation. The results demonstrated a fourfold increase in carboxylate yield with the addition of yeast. In-situ ethanol production facilitated the conversion of short-chain carboxylic acids into medium-chain carboxylates, achieving a yield of 46.3 mM-C/g VS. The presence of yeast significantly enhanced substrate utilization from 20 % to 80 %, steering the metabolic pathway towards chain elongation. Metagenomic analysis further revealed metabolic shifts following yeast addition, particularly an increased abundance of genes involved in acetyl-CoA production. Notably, the aldehyde:ferredoxin oxidoreductase (AOR) pathway emerged as a key driver in butanol production. These findings highlight the improved performance of anaerobic microalgae fermentation with yeast, enabling efficient production of higher value bioproducts while eliminating the need for external electron donors.

The state of decentralization of the healthcare system and nutrition programs in the Lao People’s Democratic Republic: an organizational study

BackgroundThe Lao People’s Democratic Republic (Lao PDR), a lower-middle income country, has a higher malnutrition rate than other Southeast Asian countries. The decentralization of healthcare is a determinant of the effectiveness of programs to reduce malnutrition, but no study has focused on this factor in this country. This organizational study explores the state of decentralization of the healthcare system in Lao PDR that underlies the nutrition programs in the country.MethodsA qualitative study, which is based on a neo-institutional theory conceptual framework, explored factors related to dominant structure (laws, regulations, resources) and interpretative schemes (dominant ideas and beliefs) that characterize the nutrition services provided in the Lao healthcare system. Twenty-four semistructured interviews were performed with representatives of healthcare institutions involved in nutrition programs at different government levels, external donors and civil society organizations. The interviews were completed with relevant documents. The analysis focused on the convergence of interpretative schemes of the organizations concerned and the coherence between the structure underpinning the nutrition programs and the interpretative schemes.ResultsServices deployed to reduce malnutrition in the Lao PDR remain largely centralized, despite factors specific to the country that led it to promote decentralization of its services. The convergence of interpretive schemes and the coherence between the observed structure and the interpretative schemes of actors at all governance levels ensure the stability of this state of decentralization, which has persisted for almost 50 years.ConclusionNutrition programs in the Laos PDR are largely under the responsibility of the central government. The transformations in the healthcare system, notably with the use of new information technologies and the fact that the provinces are populated by a growing number of professionals trained in nutrition in addition to factors that push the system to be decentralized, such as ethnic diversity, the increasing availability of human resources in provinces, and the use of communication technologies, are not strong enough to change the balance of power between governance levels. The deconcentration that characterizes decentralization is therefore likely to continue for the foreseeable future.

ASSESSMENT OF FINANCING ADULT AND NON-FORMAL EDUCATION PROGRAMS IN GOMBE STATE

This study assessed the financing of Adult and Non-Formal Education (ANFE) programs in Gombe state. Three specific objectives and three research questions were formulated. Descriptive survey design was adopted and population of the study was 325 respondents which comprise 15 administrators and 310 instructors drawn from the 15 government own Adult Education Centers in Gombe state. A sample of 169 respondents was used for the study. That is 15 administrators and 154 instructors. Instrument used was a structured questionnaire with a four rating scale titled “Assessment of Financing Adult and Non-Formal Education Questionnaire (AFANFEQ)". It was validated by two experts in the Department of Educational Foundation, Faculty of Education, Gombe State University. Pilot study was carried out and Cronbach’s Alpha was used to compute the reliability coefficient of 0.97. Descriptive statistics (mean and standard deviation) was used to answer the research questions. The findings of the study revealed that Government, Philanthropists, Community members, Adult learners and NGOs such as UNESCO, World Bank and UNDP contribute in the funding of ANFE in Gombe State but over dependence on external donors, lack of political will, inefficient resource management, embezzlement by government officials and inadequate policy support affected and serve as barriers to efficient financing of ANFE in Gombe state. It was therefore recommended among others that there is need to advocate for stronger political commitment to ANFE in Gombe state. This can be achieved through lobbying, raising public awareness, forming alliances with influential stakeholders, and demonstrating the socio-economic benefits of investing in lifelong learning opportunities. KEY WORDS: Financing, Adult and Non-Formal Education Programs

Comparative analysis of sulfur-driven autotrophic denitrification for pilot-scale application: Pollutant removal performance and metagenomic function

Two parallel pilot-scale reactors were operated to investigate pollutant removal performance and metabolic pathways in elemental sulfur-driven autotrophic denitrification (SDAD) process under low temperature and after addition of external electron donors. The results showed that low temperature slightly inhibited SDAD (average total nitrogen removal of ∼4.7 mg L−1) while supplement of sodium thiosulfate (stage 2) and sodium acetate (stage 3) enhanced denitrification and secretion of extracellular polymeric substances (EPS), leading to the average removal rate of 0.75 and 1.01 kg N m−3 d−1, respectively with over twice higher total EPS. Correspondingly, nitrogen and sulfur related microbial metabolisms especially nitrite reductase and nitric oxide reductase encoding were promoted by genera including Thermomonas and Thiobacillus. The variations revealed that extra sodium acetate improved denitrification and enriched more SDAD-related microorganisms compared with sodium thiosulfate, which potentially catalyzed the refinement of practical strategies for optimizing denitrification in low carbon to nitrogen ratio wastewater treatment.

Rehabilitation of Heritage Buildings in Conflict Zones: A Case Study of Al-Khader Library in Gaza Strip and Its Impact on Sustainable Development

Rehabilitating heritage buildings is a common practice in developed countries. In contrast, developing countries experiencing conflict lack the financial support and qualified experts to restore heritage buildings. This article focuses on the restoration of the al-Khader building in the Gaza Strip, part of a UNESCO project aimed at preserving historical buildings. This study aims to explore the challenges and impacts of the adaptive reuse of the al-Khader building as a children’s library for the local community and to explore the impact of this project on sustainable development and its importance locally, as well as the role of this building restoration and rehabilitation through Quintuple Helix dimensions. Qualitative methodology was used, including field observation and interviews, to present the project stages during restoration in 2016. The interviews were conducted with library users, employees, and visitors to evaluate their experience in 2019. The research revealed that the restoration process faced several challenges, including a lack of experience and professional workers in conservation work. Despite challenges, the building’s transformation positively affected heritage preservation and the local community, aligning with 11 Sustainable Development Goals—directly with 7 goals (SDGs 4, 7, 8, 11, 12, 16, and 17) and indirectly with 4 goals (SDGs 1, 5, 9, and 13). The findings emphasise the role of the library’s rehabilitation in contributing to the success of the Quintuple Helix in economic and civil society systems and the need to enhance the consideration of government, education, and environmental systems. Finally, this project, which external donors funded, increased awareness among local people of the importance of heritage buildings. Unfortunately, due to the ongoing conflict in Gaza, the current status of the building is unknown. This study, therefore, serves as necessary documentation of the building as it was in 2023 and prior.

The Impact of Socioeconomic Factors on HIV Prevalence and Treatment Accessibility in Nigeria: A Comprehensive Review

HIV/AIDS remained a major public health challenge in Nigeria, with approximately 1.9 million people living with HIV (PLHIV), making it one of the most affected countries globally. This comprehensive review explored the impact of socioeconomic factors on HIV prevalence and treatment accessibility in Nigeria, focusing on key determinants such as poverty, education, gender inequality, and geographic disparities. Poverty exacerbated the risk of HIV infection by limiting access to prevention resources and creating barriers to treatment, while educational disparities affect awareness and prevention behaviors. Gender inequality, particularly in patriarchal societies, increases women’s vulnerability to HIV due to limited control over sexual health decisions and economic dependence. Geographic disparities, especially between urban and rural areas, contributed to uneven HIV prevalence and treatment access, with rural regions often facing significant healthcare infrastructure challenges. Additionally, the strength of health system infrastructure and funding played a crucial role in shaping the effectiveness of HIV services, with underfunding and reliance on external donors posing significant risks to sustainability. The methodology used in this article involved a review and synthesis of existing literature and data on HIV/AIDS in Nigeria, emphasizing the socioeconomic determinants of the epidemic. Addressing these factors required targeted interventions, such as strengthening social protection programs, enhancing education, promoting gender equality, improving healthcare infrastructure, and ensuring sustainable funding. These efforts were essential for reducing HIV prevalence and improving treatment outcomes in Nigeria. Keywords: HIV/AIDS, Socioeconomic determinants, Nigeria, Healthcare infrastructure, Gender inequality.

Teachers implementing Zimbabwean sign language regulatory frameworks for deaf learners in special schools

Effective implementation of sign language-based instruction is crucial for providing quality education to Deaf learners at special schools. Teachers experienced challenges to effectively implement sign language policies for the Deaf learners in Zimbabwean special schools. However, this study explores how teachers implement sign language regulatory frameworks for Deaf Learners in special schools. Drawing on qualitative data from teachers, headmasters, school inspectors, and psychologists. The findings revealed critical gaps in the in-service training and professional development opportunities available to teachers serving Deaf students. Despite teachers reporting difficulties with sign language fluency and inadequate understanding of Deaf culture and pedagogy, the study found a disconnect between teachers' expressed needs and the perspectives of district-level officials, who often did not perceive additional training as necessary. This study further highlights the heavy reliance on support from external donor organizations and NGOs to provide teachers with limited sign language workshops and resources. This overreliance on precarious external funding sources compromises the sustainability and scalability of professional development initiatives. The study's implications call for a comprehensive, government-led strategy to ensure all teachers in Deaf schools receive robust, long-term training in sign language, Deaf education methodologies, and Deaf cultural competence. Strengthening the capacity of the teaching workforce is essential for upholding the rights of Deaf learners to receive instruction in their primary language and achieving meaningful implementation of sign language policies. This study contributes vital empirical evidence to inform policy reforms and teacher training programmes to support using Zimbabwean Sign Language as a medium of instruction for the Deaf.

Differences on carboxylic acids bioproduction from soluble carbohydrates or proteins in a sequencing batch reactor: Deciphering the influence of the volumetric and specific organic loading rate

Acidogenic fermentation (AF) has been extensively explored. However, the impact of operational parameters on AF has led to inconsistent results. In this work, AF experiments were performed in a sequencing batch reactor (SBR) using simulated wastewaters solely containing soluble carbohydrates or proteins as carbon sources to independently assess the impact of the volumetric organic loading rate (OLRv) and of the specific organic loading rate (OLRs). When only carbohydrates were used, the main effluent components were acetic and butyric acids at OLRv of 6.0 g COD L−1 d−1, while changing OLRv over 11.0 g COD L−1 d−1 gave acetic acid and ethanol as main components. Conversely, if the carbon source consisted solely of proteins, increasing the OLRv or the OLRs had minimal impact on the AF performance and on the effluent composition. Also, in the case of carbohydrate experiments, increasing the OLRs from 2.3 to 3.8 g COD g−1 VSS d−1 promoted chain elongation reactions, as caproic acid formation was also observed. Besides, at the highest OLRv tested in this work for protein experiments (18.5 g COD L−1 d−1), it was obtained the maximum isocaproic acid concentration using mixed microbial cultures and without adding any external electron donor. The SBR configuration proved to be an adequate system, especially when proteins were used as carbon source, since it makes possible to keep low the OLRs and to reduce the hydrolysis limitations. Finally, the bacterial genera detected in the reactors notably changed between both substrates. Future work must be focused on identifying carboxylic acid producing-genera from proteins.

Enhancing collaboration of anammox with heterotrophic microbes mediated selectively by iron of different valences: Activities balance, metabolic mechanism, and functional genes regulation

The partial denitrification/anammox (PD/A) process is receiving increasing attention due to its cost-effectiveness advantages. However, effective strategies to alleviate organic matter inhibition and promote anammox activity have been proven to be a big challenge. This study investigated the effects of three types of iron (nano zero-valent iron (nZVI), Fe(II), and Fe(III)) on the PD/A process. It is worth noting that nZVI of 5–50 mg/L and Fe(III) of 5–120 mg/L promoted both PD and anammox activity. Long-term intermittent addition of nZVI (50 mg/L) resulted in a nitrogen removal efficiency of 98.2% in the mixotrophic PD/A system driven by iron and organic matter. The contribution of anammox for nitrogen removal reached as high as 93.8%. The organic carbon demand decreased due to the external electron donor provided by nZVI for PD. Multiple Fe–N metabolic pathways, primarily involving ammonia oxidation by Fe(III) and nitrate reduction by nZVI, play a crucial role in facilitating nitrogen transformation. Conversely, the direct addition of 30–120 mg/L Fe (II) resulted in a significant decrease in pH to below 5.0 and severe inhibition of PD and anammox activity. Following prolonged operation in the presence of nZVI, it was demonstrated that there is an enhancing effect on robust nitrite production for anammox. This was accompanied by a remarkable up-regulation of genes encoding nitrate reductase and iron-transporting proteins dominated by Thauera. Overall, this study has provided an efficient approach for advanced nitrogen removal through organic- and iron-driven anammox processes.

Extracellular electron transfer explained

Extracellular electron transfer explained Arpita Bose, PhD from Washington University in St. Louis, guides us through host-associated impacts and biotechnological applications of extracellular electron transfer in electrochemically active bacteria. Electron flow and oxidative and reductive reactions, referred to as “redox reactions,” collectively impact the outcomes of biochemical pathways essential for cell growth, energy conservation, and stress response throughout various organisms. An example of these organisms is electrochemically active bacteria (EAB), which can link internal redox reactions with external electron acceptors or donors via a process known as extracellular electron transfer (EET).

External electron donor and transporter of iron triggers the paths to enhancing collaboration of anammox and denitrification in granular sludge: Bacterial resilience and synergetic promotion mechanism

Autotrophic nitrogen removal via anaerobic ammonium oxidation (anammox) technology currently faces significant challenges in treating low-strength wastewater due to inefficient retention of bacteria and unstable activity under fluctuating conditions. This study demonstrates enhanced resilience and stability of anammox coupled with partial denitrification (PD) in granular sludge, assisted by ferric iron (Fe(III)) and nano zero-valent iron (nZVI). The systems treated wastewater with low concentrations of ammonia (NH4+-N of 50 ∼ 80 mg/L) and nitrate (NO3−-N of 60 ∼ 100 mg/L). Fe(III) and nZVI were intermittently added to two PD coupled with anammox (PD/A) systems, which were subjected to increasing nitrogen loading rates (NLRs) and decreasing temperature. Remarkably, both Fe(III)- and nZVI-assisted systems achieved satisfactory total nitrogen (TN) removal efficiencies of 98.1 % and 96.6 %, respectively, even as the temperature dropped from 28.5℃ to 13.4℃ and the NLR increased from 0.22 to 0.72 kgN/m3/d. Significantly, these two systems exhibited pronounced resilience under the shocking effect of excessive organic load, extremely low pH, and high salinity. The presence of iron, acting as an accelerated electron transporter, enhanced anammox activity and microbial NH4+-N oxidation. Additionally, iron reduced the requirement for an organic carbon source, further stimulating the competitiveness of anammox for nitrite (NO2−-N) against denitrification. Interestingly, metagenomic analysis revealed that the functional bacteria Thauera, responsible for PD, employed versatile metabolic pathways for NO3−-N reduction to NO2−-N using Fe(II) as an electron donor. Overall, this study provides new insights into microbial interactions and versatile metabolism in iron-assisted anammox systems, contributing to more energy-efficient wastewater treatment.

Probing ligands to reaction centers to limit the photocycle in photosynthetic bacterium Rubrivivax gelatinosus

Light-induced electron flow between reaction center and cytochrome bc1 complexes is mediated by quinones and electron donors in purple photosynthetic bacteria. Upon high-intensity excitation, the contribution of the cytochrome bc1 complex is limited kinetically and the electron supply should be provided by the pool of reduced electron donors. The kinetic limitation of electron shuttle between reaction center and cytochrome bc1 complex and its consequences on the photocycle were studied by tracking the redox changes of the primary electron donor (BChl dimer) via absorption change and the opening of the closed reaction center via relaxation of the bacteriochlorophyll fluorescence in intact cells of wild type and pufC mutant strains of Rubrivivax gelatinosus. The results were simulated by a minimum model of reversible binding of different ligands (internal and external electron donors and inhibitors) to donor and acceptor sides of the reaction center. The calculated binding and kinetic parameters revealed that control of the rate of the photocycle is primarily due to 1) the light intensity, 2) the size and redox state of the donor pool, and 3) the unbinding rates of the oxidized donor and inhibitor from the reaction center. The similar kinetics of strains WT and pufC lacking the tetraheme cytochrome subunit attached to the reaction center raise the issue of the physiological importance of this subunit discussed from different points of view. SignificanceA crucial factor for the efficacy of electron donors in photosynthetic photocycle is not just the substantial size of the pool and large binding affinity (small dissociation constant KD = koff/kon) to the RC, but also the mean residence time (koff)−1 in the binding pocket. This is an important parameter that regulates the time of re-activation of the RC during multiple turnovers. The determination of koff has proven challenging and was performed by simulation of widespread experimental data on the kinetics of P+ and relaxation of fluorescence. This work is a step towards better understanding the complex pathways of electron transfer in proteins and simulation-based design of more effective electron transfer components in natural and artificial systems.

Medium-chain carboxylates production from plant waste: kinetic study and effect of an enriched microbiome

BackgroundThe need for addition of external electron donors such as ethanol or lactate impairs the economic viability of chain elongation (CE) processes for the production of medium-chain carboxylates (MCC). However, using feedstocks with inherent electron donors such as silages of waste biomass can improve the economics. Moreover, the use of an appropriate inoculum is critical to the overall efficiency of the CE process, as the production of a desired MCC can significantly be influenced by the presence or absence of specific microorganisms and their metabolic interactions. Beyond, it is necessary to generate data that can be used for reactor design, simulation and optimization of a given CE process. Such data can be obtained using appropriate mathematical models to predict the dynamics of the CE process.ResultsIn batch experiments using silages of sugar beet leaves, cassava leaves, and Elodea/wheat straw as substrates, caproate was the only MCC produced with maximum yields of 1.97, 3.48, and 0.88 g/kgVS, respectively. The MCC concentrations were accurately predicted with the modified Gompertz model. In a semi-continuous fermentation with ensiled sugar beet leaves as substrate and digestate from a biogas reactor as the sole inoculum, a prolonged lag phase of 7 days was observed for the production of MCC (C6–C8). The lag phase was significantly shortened by at least 4 days when an enriched inoculum was added to the system. With the enriched inoculum, an MCC yield of 93.67 g/kgVS and a productivity of 2.05 gMCC/L/d were achieved. Without the enriched inoculum, MCC yield and productivity were 43.30 g/kgVS and 0.95 gMCC/L/d, respectively. The higher MCC production was accompanied by higher relative abundances of Lachnospiraceae and Eubacteriaceae.ConclusionsEnsiled waste biomass is a suitable substrate for MCC production using CE. For an enhanced production of MCC from ensiled sugar beet leaves, the use of an enriched inoculum is recommended for a fast process start and high production performance.

Oxygen-enriched carbon quantum dots from coffee waste: Extremely active organic photocatalyst for sustainable solar-to-H2O2 conversion

Solar-driven artificial photosynthesis offers a promising avenue for hydrogen peroxide (H2O2) generation, an efficient and economical replacement for current methods. The efficiency and selectivity hurdles of the two-electron oxygen reduction reaction (ORR) in solar-to- H2O2 conversion are substantial barriers to large scale production. In this manuscript, a simple biomass-assisted synthesis was performed to produce oxygen-enriched carbon quantum dots (OE-CQDs) from spent coffee waste, acting as an efficient photocatalyst for solar-powered H2O2 production. OE-CQDs can stabilize and store light-generated electrons effectively, boosting charge separation and enhancing photocatalytic performance with longevity. The maximal photocatalytic H2O2 production was achieved viz the utilization of OE-CQDs with generation rate of 356.86 μmol g-1 h-1 by retaining 80% activity without any external sacrificial donors. The outstanding performance of synthesized OE-CQDs under light exposure at wavelength (λ) of 280 nm has been ensured by the quantum yield value of 9.4% upon H2O2 generation. The combinatorial benefits of OE-CQDs with their authentic crystalline structure and oxygen enrichment, is expected to be enhancing the ORR activity through accelerating charge transfer, and optimizing oxygen diffusion. Consequently, our eco-friendly method holds considerable promise for creating highly efficient, metal-free photocatalysts for artificial H2O2 production.

Decentralization and immunization program in a single-party state: the case of the Lao People’s Democratic Republic

BackgroundThe Lao People’s Democratic Republic (Lao PDR), a lower-middle-income country, lags behind other Southeast Asian countries in immunization coverage for children under two years of age. The organization of health services is a key determinant of the functionality of immunization programs. However, this aspect, and in particular its decentralization component of the healthcare system, has never been studied.MethodsA case study in the Lao National Immunization Program was performed using a neo-institutional theory-based conceptual framework, highlighting the structure (rules, laws, resources, etc.) and interpretative schemes (dominant beliefs and ideas) that underlie the state of decentralization of the healthcare system that support the conduct of the immunization program. Twenty-two semi-structured interviews were conducted with representative actors from various government levels, external donors, and civil society, in four provinces. Data were complemented with information retrieved from relevant documents.ResultsThe Lao healthcare system has a deconcentrated form of decentralization. It has a largely centralized structure, albeit with certain measures promoting the decentralization of its immunization programs. The structure underlying the state of centralization of immunization services provided is coherent with a shared dominant interpretive scheme. However, the rapid economic, technical, and educational changes affecting the country suggest that the coherence between structure and interpretative schemes is bound to change.ConclusionUnprecedented opportunities to access quality higher education and the use of social networks are factors in Lao PDR that could affect the distribution of responsibilities of the different levels of government for public health programs such as the National Immunization Program.

A DFT study on the role of alkoxysilanes in the polymerization of isoprene over Ziegler-Natta catalyst

Ziegler-Natta catalysts are widely used in the production of polyolefin with the advantages of low cost and high efficiency. The external electron donors are usually used during the polymerization to obtain the polyolefins with higher isotacticity. Four alkoxysilanes external electron donors were investigated by Density Functional Theory (DFT) calculations. Local Electron Attachment Energy (LEAE) calculations showed that alkoxysilanes tend to adsorb at the Mg1 site and the Mg4 site of the MgCl2(110) surface (The first and fourth Mg atoms from right to left on the MgCl2(110) surface, respectively), and that differences in substituents have a large effect on the stability of alkoxysilanes adsorption. In addition, it was found that the adsorption of alkoxysilanes at the Mg1 site affects the active center in two ways, decreasing the electron cloud density of the active center Ti and increasing the steric hindrance of the active center Ti. Comparing the four alkoxysilanes, it is found that DIPMS can maximize the regional selectivity of catalysts, while DCPDMS can maximize the stereoselectivity of catalysts.